Synthesis, crystal structures and spectral studies of square planar nickel(II) complexes containing an ONS donor Schiff base and triphenylphosphine

Abstract

Five mononuclear nickel(II) complexes, viz. [Ni(L1)(PPh<inf>3</inf>)] (1), [Ni(L2)(PPh<inf>3</inf>)] (2), [Ni(L3)(PPh<inf>3</inf>)] (3), [Ni(L4)(PPh<inf>3</inf>)] (4) and [Ni(L5)(PPh<inf>3</inf>)] (5) (where L1, L2, L3, L4 and L5 are dianions of N-(2-mercaptophenyl)salicylideneimine, 5-methyl-N-(2-mercaptophenyl)salicylideneimine, 5-chloro-N-(2-mercaptophenyl)salicylideneimine, 5-bromo-N-(2-mercaptophenyl)salicylideneimine and N-(2-mercaptophenyl)naphthylideneimine, respectively), have been synthesized and characterized by means of elemental analysis, electronic, IR, 1H, 13C and 31P NMR spectroscopy. Single crystal X-ray analysis of two of the complexes (1 and 5) has revealed the presence of a square planar coordination geometry (ONSP) about nickel. The crystal structures of the complexes are stabilized by intermolecular ?-? stacking between the ligands (L) and by various C-H···? interactions. © 2009 Elsevier Ltd. All rights reserved.